Dermatopathology - Benign and Malignant Tumors 2024 PDF

Dermatopathology-benign and malignant tumors Jin Guo, MD 2024 Objectives: By the end of the lecture, the students should be able to recognize and discuss the diagnostic features of: Pigmented neoplasm of skin – Melanocytic nevus – Melanom...

Dermatopathology-benign and malignant tumors Jin Guo, MD 2024 Objectives: By the end of the lecture, the students should be able to recognize and discuss the diagnostic features of: Pigmented neoplasm of skin – Melanocytic nevus – Melanoma – Other pigmented lesions Epidermal and dermal neoplasm of skin – SCC, BCC  Papillary dermis Image result for mitosis histology Reticular dermis Case A 52-year-old woman presented with a pigmented papule on the dorsum of the right hand, measuring 5 mm in diameter.  6 months later, the patient reported a recent change in size, 1.5 cm. Punch Shave parakeratosis Abnomral melanocytes in the upper layer of demis in situ component of this melanoma The diagnosis of superficial spreading malignant melanoma was made  Melanoma ~122,000 new cases ~75% of all skin tumor deaths are from melanoma 8,700 people expected to die every year Median age of diagnosis 59 years Most common malignancy in young adults 25-29 years old Melanoma Melanoma Radial growth phase -Lack of maturation with descent -Cytologic atypia & nuclear pleomorphism -Mitoses - deep dermal, often Vertical growth phase atypical What is the relationship between this thickness and the prognosis? Melanoma Distance between the granular layer of the epidermis and the deepest melanoma cell inflammatory response What is the most important prognostic indicator? Thickness of melanoma determines pathology stage and margins for excision Stage and margins required: pTis (in situ): 5 mm margin pT1 (4.0 mm): 2 cm margin – A wider margin (2 cm) is optimal, where possible, depending on tumor site and surgeon/patient preference.  Melanoma - Important histologic prognostic parameters Thickness (Breslow depth): measured in mm from granular cell layer to deepest dermal extension Ulceration Mitotic rate (mitoses/mm2) Microsatellitosis Neurotropism Angiolymphatic invasion  Melanoma Histologic features – Lack of maturation with descent – Cytologic atypia & nuclear pleomorphism – Large & irregular nucleoli – Deep dermal, often atypical mitosis – Increased apoptosis Melanoma types Superficial spread Most common type of MM in the white-skinned population - 70% of cases Commonest sites - lower leg in female and back in males In early stage it may be small, then growth becomes irregular Melanoma types Nodular Common in males Trunk is a common site Usually with a poor prognosis Black/brown nodule Ulceration and bleeding are common Melanoma types Lentigo maligna melanoma Mainly on the face in elderly patients May be many years before an invasive nodule develops Melanoma types Acral lentiginous melanoma Common in black people and Asian In white-skinned population accounting for 10% of MM Usually comprises a flat lentiginous area with an invasive nodular component Melanoma types Subungal melanoma Rare Often diagnosed late - confusion with benign subungal nevus, infections or trauma Melanoma types Conjunctival melanoma Melanoma types Amelanocytic melanoma Diagnosis is often missed clinically The lack of pigmentation is due to the rapid growth of the tumor and the differentiation of the malignant melanocytes  Metastatic melanoma Satellitosis near the primary melanoma Sometimes distant metastases that appear as papules or plaques, not pigmented. Melanoma metastatico  Diagnosis? Malignant melanoma -Small size, circumscription and symmetry -Nested proliferation with regular distribution -Melanocyte nuclei small -Uniform cellular density -Melanocytes decrease in size towards base of lesion ("maturation") -Absence of mitotic activity (particularly at base of lesion) -Lack of necrosis and cytologic atypia Junctional nevus intradermal nevus Compound nevus This brown, pigmented lesion with hairs was present at birth. The diameter of this nevus is a few centimeters. Congenital melanocytic nevi Tends to involve reticular dermis, subcutis, Is there increased melanoma skin adnexa --- risk for this patient? Neural differentiation Frequent proliferative nodules Pigmented macule with irregular borders (smaller than MM) Dysplastic nevus -Nested atypical melanocytes with bridging rete ridges What is the risk of developing a malignant melanoma in these lesions? Familial atypical multiple mole and melanoma syndrome - more than 100 nevi, many of them dysplastic - a lifetime risk of malignant melanoma approaches 100%.  Non melanocytic neoplasm of skin Case A 67-year-old man with a round, nodular, pearly lesion on the left cheek, 12 mm, for 6 months Dilated subepidermal blood vessels (telangiectasias) When he washes his face, the crust comes off and the lesion starts bleeding Basal cell CA -Basaloid tumor islands -Peripheral palisading of nuclei -Stromal retraction artifact -Stromal solar elastosis Basal cell CA  Basal cell carcinoma Most common type of skin cancer Derived from basal cell layer of epidermis Chronic sun exposure is major risk factor Translucent or “pearly” nodule or plaque Head and neck of elderly patients Slow, progressive growth Locally destructive, recurs, rarely metastasizes Types of BCC Superficial BCC: Superficial BCC -Tends to occur in younger patients -Often multiple multicentric -Pink or red scaly irregular plaques -Bleed or ulcerate easily Types of BCC Micronodular BCC: Nodular BCC -Micronodular type often -Most common type on the face infiltrate deeply -Small, shiny, skin coloured or pinkish lump -Blood vessels cross its surface  Basal cell carcinoma Types of BCC Superficial BCC: Pigmented BCC -Brown, blue or greyish lesion -Nodular or superficial histology -May resemble melanoma -But typical pallasiding if any doubt, IHC Types of BCC Superficial BCC: Pleomorphic BCC Types of BCC Sclerosing BCC: Infiltrative growth BCC: -Prone to recur after treatment -May infiltrate cutaneous nerves (perineural spread)  BCC - histological features Almost always epidermal attachment Nests or lobules of hyperchromatic but uniform basaloid cells with peripheral palisading, surrounded by loose stroma Cleft-like retraction spaces May appear pigmented due to dermal melanophages Sun-damaged skin on the balding scalp of an elderly man. Actinic keratosis Squamous cell carcinoma in-situ normal Actinic karatosis This large actinic keratosis is present on the balding scalp of an elderly man. In the center, a nonhealing ulcer is present. Squamous cell carcinoma Squamous cell carcinoma Usually men Very rare in blacks Slow growing, locally invasive but rarely metastasizes outside nodes 5% are node positive at diagnosis Prognosis: – Excellent – Metastases uncommon if tumor < 1.5 cm deep – 5% metastasize if 2 cm or more and definite dermal invasion; most common site is lung Treatment: Surgical excision with adequate margins  Other pigmented lesion Case A 55-year-old man sees his doctor because of firm, brown papules on his back. The lesion is oval, has a diameter of 14 mm and surfaces 3 mm above the surrounding skin level. The patient worries that he might have a malignant melanoma. There is no bleeding, itching or pain. – Dark brown lesions – Greasy-appearing, granular surface – Clearly elevated above the surrounding skin level  Seborrheic keratosis Thickened epidermis: Acanthosis Leser-Trélat sign What must be considered when numerous of these lesions occur explosively?  Summary – Neoplastic skin diseases Pigmented neoplasm of skin – Melanoma – Melanocytic nevus – Other pigmented lesion Epidermal and dermal neoplasm of skin – BCC, SCC, Normal Skin with sun damage (solar elastosis) AK or SCC; BCC; MM  A. Pigmented basal cell carcinoma B. MM A C. Seborrheic keratosis B D. Compound naevi C D Atypical melanocytes in the epidermis – melanoma insitu Malignant melanoma The superficial subtype of basal cell carcinoma Nodular BCC squamous cell carcinoma insitu Well-differentiated squamous cell carcinoma